Apparatus for the manufacture of venetian blind ladder tape



Dec. 9, 1952 Filed Nov. 2. 1948 E. JANOWSKI APPARATUS FOR THEMANUFACTURE OF VENETIAN BLIND LADDER TAPE 9 Sheets-Sheet 1 Fig.l.

INVENTOR. Edward donowskl ATTORNEY Dec. 9, 1952 E. JANOWSKI' 2,520,350

APPARATUS FOR THE MANUFACTURE OF VENETIAN BLIND LADDER TAPE 9Sheets-Sheet 2 Filed Nov. 2, 1948 IN V EN TOR.

Dec. 9, 1952 JANOWSK] 2,620,850

APPARATUS FOR THE MANUFACTURE OF VENETIAN BLIND LADDER TAPE Filed Nov.2, 1948 9 Sheets-Sheet 3 Fig.3

IN V EN TOR.

Edwdrd Jcmowsld ATTORNEY Dec. 9, 1952 JANOWSK] 2,620,850

APPARATUS FOR THE MANUFACTURE OF VENETIAN BLIND LADDER TAPE Filed Nov.2, 1948 9 Sheets-Sheet 4 Fig.5

IEE d INVENTORk v dwor onows i ATTORNEY Dec. 9, 1952 V A -K 2,620,850

- APPARATUS FOR THE MANUFACTURE OF VENETIAN BLIND LADDER TAPE v FiledNov. 2, 1948 9 Sheets-Sheet 5 Fig. I l E6 I (F 76 26%.] 2 56b #69 66 42G 1 i l QM F X i l K [6g 60 M6 5% 44 7 flag Fig. l2

44 INVENTOR.

Edward Jonowski Wm M ATTORNEY Filed Nov. 2, 1948 Dec. 9, 1952 E JANQWSK]2,620,850

APPARATUS FOR THE MANUFACTURE OF VBNETIAN BLIND LADDER TAPE 9Sheets-$heet 6 a? 25/ a 53/ 5E 6c? a4 I E34 $7 50 232 T T 2:22 5%? 52 H606 E06 44 f I I f 8/0 44 3/2 606 2/5 2 E04 /98 Z J 220 I Fug. I3

INVENTOR.

ATTORNEY Dec. 9, 1952 E. JANOWSKI 0,

APPARATUS FOR THE. MANUFACTURE OF VENETIAN BLIND LADDER TAPE 9Sheets-Sheet 7 Filed Nov. 2, 1948 INVTOR. Edward .Janowskl lEb Fig. l8

ATTORNEY-- Dec. 9, 1952 JANOWSK! Filed NOV. 2. 1948 E. APPARATUS FOR THEMANUFACTURE OF VENETIAN BLIND LADDER TAPE 9 Sheets-Sheet 9 Fig. 2|

INVENTOR. 7. Edward JOHOWSKI ATTORN EY Patented Dec. 9, 1952 UNITEDSTATES PATENT OFFICE Edward Janowski, Pawtucket, R. I.

Application November 2, 1948, Serial No. 57,912

8 Claims.

My invention relates to improvements in plastic ladder tape for Venetianblinds and improved methods and apparatus for its manufacture.

An object of my invention is to provide a plastic ladder tape forVenetian blinds constructed entirely or substantially entirely out ofplastic.

Objects of my invention, therefore, are to provide a novel type ofplastic tape which may be transparent, translucent or opaque, which canbe embossed or printed on or can have silver or gold leaf securedthereto, or which can be otherwise dyed or ornamented in novel fashionsnot possible with the woven tape of the prior art. In addition, such atape may be dyed a light fast color, faster than possible with woventapes and may provide in use a glossy sheen, which is a pleasingnovelty, particularly if the tape itself is translucent or transparent.

The greatest objection, and one that limits the demand for Venetianblinds is the periodical, necessary changing of ladder tapes, because ofcolor fading and general deterioration. My plastic ladder tape lasts aslong as the slats, eliminating this undesirable feature of ladder tapenow on the market.

A further object of my invention is to provide a tape which iswaterproof, dustproof, mildewproof, resistant to dry rot, has straightnon-wavy edges and which is chemical and vapor resistant and which isless inflammable than woven tape.

A further object of my invention is to provide such ladder tape whichmay be readily cleaned by merely wiping it off with a damp cloth andfrom which oil stains and grease forming finger marks may be readilyremoved and also are not readily received thereon.

A further object of my invention is to provide such a ladder tape whichis nonstretching in use, either from the inherent structure of theladder tape or by the use of stretch limiting cords incorporated thereinin a hidden manner.

A further object of my invention is to provide a tape in which theladders are secured to the tape side portions with an extremely tightbond, so tight that the side tapes themselves will tear instead of thebond pulling off, and one in which the spacing of each ladder isabsolutely accurate, much more accurate than is possible with woventapes.

Further objects of my invention relate to my improved method ofmanufacture of said tape which comprises inserting the plastic rungsbetween the spaced plastic ladder tapes, with the ends thereof bentagainst said tapes for a substantial distance and applying welding radiofrequency heat through said turned ends and opposite tape portions toweld said ends to said tape portions with the tape itself acting as adielectric, preferably while additionally conducting said electriccurrent between said aligned ends to obtain a greater heat.

A further feature of my invention relates to the provision of a machinefor making my improved type of tape particularly adapted for use inradio frequency dielectric welding, although other types of means may beemployed to secure the ends of the ladders to the tape, if desired.

A further object of my invention is to provide a machine for thispurpose which is the essence of simplicity merely providing means toinsert plastic ladder tapes between continuous runs of moving sidetapes, stopping the runs of said side tapes while welding them, and thencontinuing their forward run involving broadly two main steps, namely,(a) the initial assembly, and (b) the securing.

While in my improved machine, I weld the ends of two staggered rungs tothe side ladder strips as usual, it is obvious that my method may beemployed for welding one of a large plurality of rung ends to the sidetapes if desired in use.

It is obvious that this method has many advantages over weaving thetapes. The cross stitch which has to be cut is eliminated. Manyoperations in the manufacture of the individual threads are eliminated.The dyeing is also eliminated and the device may produce tape severalhundred percent faster than can be done on a loom, welding four ends atthe same time, it being obvious that this percentage may be greatlyincreased in the event that more than four rung ends are welded at thesame time.

A further object of my invention is to provide a machine which may, ifdesired, weld a plurality of rung ends at once.

A further object of my invention is to provide a machine taking up aminimum of floor space per unit.

A further object of my invention is to provide a machine in which it iseasy to change over from one color to another.

A further object of my invention is to provide a machine in which theaccuracy of spacing is positively identical and automatic and much moreaccurate than that provided in a loom where it has been found that eachloom provides a slightly different spacing.

A further object of my invention is to provide a machine which is fullyautomatic in its action.

A further object of my invention is to provide a machine particularlyadapted for use in radio frequency dielectric welding which willfunction to give a strong bond with a smaller electronic unit withoutarcing. Arcing presented one of the greatest problems in the developmentof the machine and I have found that if the electrodes are universallymounted on the devices employed for reciprocating them into positionthat the arcing was substantially reduced.

A further object of my invention relates to the provision of a machineincluding an intermittently movable conveyor on which the ladder rungsare successively mounted and brought into position between thecontinuous side tapes, so that the ends thereof will bend backwardly inthe same direction in a position for welding. All the operations maytake place on a single run of the conveyor, but in the embodiment shownI preferably provide a rung loading means on the upward straight rearrun of the conveyor and a welding on the downward straight front run ofthe conveyor.

A further feature of my invention lies in the structure of jigs I employto insulatedly mount the rung holders on the conveyor, preferablycomprising supporting cross conducting rods on which the rungs aremounted to abut the inturned ends of the rungs and adjacent sideportions to provide a greater welding heat than if the current weremerely grounded on the inside of the side tapes, which jigs arepreferably provided with means to hold them in alignment on a straightrun and at 'a spaced distance apart with suitable means for automaticallclamping the rungs as they are fed into position thereon.

A further object of my invention relates tothe novel type of feedingmechanism I have provided for loading and holding the rungs on each jigarm and preferably also cutting the rungs from a source of supply, sothat the ends of each rung will extend laterally equidistantly fromtheir holding means or conducting bars.

A further feature of my invention relates to the improved meansIpreferably employ for feeding the side tapes evenly into position tohave the inturned ends of the rungs Welded or otherwise secured thereto,and the means I employ to guide said side tapes into such position.

A further feature of my invention relates to the specific type ofmechanism applying high radio frequency heat and welding, includinganovel type of electrode for this purpose, and the means of supporting itand its actuating means on the machine.

A further feature of my invention relates t the intermittent feed Ipreferably provide for the conveyor, preferably in combination with theother mechanism, to actuate all other mechanism during each stop of theconveyor, and also to an overrun stop lockI preferably employ incombination therewith.

Further features of my invention relate to the specific type of means Iemploy for actuating the various parts of my invention.

A further feature of my invention relates to the improved type of meansI employ for stripping the completed tape from the conveyor.

A further feature of my invention relates to the stop motions Ipreferably employ and the electric circuit for their functioni whichstop motions include a motion to automatically stop the machine in theevent a rung is not correctly loaded on the conveyor and a switch tostopthe 4 machine in the event the completed tape is not being strippedfrom the conveyor.

A further feature of my invention relates to the particular type ofmeans I employ to control the welding heat and limit it to the fractionof a cycle that the welding heat is required and then for a settabletime.

These and such other objects of my invention as may hereinafter appearwill be best understood from a description of the accompanying drawings,which illustrate an embodiment thereof.

In the drawings,

Fig. 1 is a front elevation of an automatic machine for intermittentlywelding plastic ladder rungs to continuous strips of spaced ladder sidetapes constructed in accordance with my invention.

Fig. 2 is a side elevation thereof.

Fig. 3 is-a rear elevation thereof.

Fig. 4 is a fragmentary rear elevation of the rung feeding mechanism.

Fig. '5 is a plan view of the rung feeding mechanism shown in Fig. 4.

Fig. -'6 is a fragmentary side elevation of the conveyor and attachedjigs passing by the feeding mechanism showing a portion thereof sectionalong the line 6-6 of Fig. 5.

Fig. 7 is a transverse sectional view-taken along the line 7-? of Fig.5.

Fig. 8 is a perspective view of the improved jig I preferablyemploy. Y

Figs. 9-12 are diagrammatic skeletonsectional views taken along the line9'-9 of Fig. 5, illustrating how the loading, holding and cuttingmechanism functions to mounta "cut rung on the'leading edge of a jigcross bar, Fig. 9 'show ing the slide advanced to its innermost positionwith the movable jaw about to nip the tape, Fig. 10, showing the deviceafter the movable jaw has fallen to nip the tape end, Fig. 11illustratinghow the movable jaw and slide function to pull the tape endacross-the open portion of the feeding mechanism in front of the leadingedge of a jig crossbar and Fig. 12 illustrating the device the act ofcutting a rung so that each end thereof will project equal amountslaterally from each end of the crossbar.

Fig. 13 is a fragmentary front elevation of a portion "of the machineshowing my "improved welding electrodes moved into welding position,showing the electrode plates and one electrode in section.

Fig. 14 is a side elevation looking outwardly towards the centre of anelectrode.

Fig. 15 is a diagrammaticexploded perspective view of my improvedelectrode structure adapted to weld the staggered ends of a pair ofadjacent rungs.

Fig. 16 is a diagrammatic side elevationalview illustrating the arms Iemploy to intermittently feed the conveyor, certain details of theoverrunning stop lock and certain details of the structure of the meansI employ to strip the completed tape from the conveyor.

Fig. 17 is an enlarged elevational view of the feeding finger Ipreferablyemploy.

Fig. 18 is a plan view of the intermittent feeding mechanism Ipreferably employ showing the slotted side guide bars in section.

Fig. 19'is a partial electricaldiagram of the welding device, sto motionmechanismsand timing device I preferably employ.

Fig. 20 is -a side elevation'of' the improved substantiallynonstretchable flexible plastic tape 1 preferably produce.

Fig. 21 is an end elevation thereof.

Fig. 22 is a sectional view thereof taken along the line 2222 of Fig.20.

Fig. 23 is a side elevation of an alternate embodiment of my inventionhaving cords welded between the inturned rung ends and the side tapes ofthe ladder tape.

Fig. 24 is a sectional view thereof taken along the line 24-24 of Fig.23.

Fig. 25 is a transverse sectional view taken along the line 25-25 f Fig.24.

In the drawings, wherein like characters of reference generally indicatelike parts throughout, generally indicates a machine for intermittentlysecuring plastic ladder rungs to continuous runs of spaced ladder tapeside strips constructed in accordance with my invention.

Broadly, said machine comprises means to insert plastic ladder rungs 32between spaced ladder tapes 34a and 34b, with the respective ends 36aand 36b of said rungs 32 bent adjacent said tapes in the same directionfor a substantial distance, in my preferred embodiment as shown in Figs.20 and 21 with alternate rungs 32 and 32' laterally staggered from eachother to provide aligned rows of rungs on each side of said tape andmeans to secure said bent ends 36a and b to said adjacent tape portions38a and 38b by the welds 40a and 402), or in any other suitable manner.

It is obvious that my machine is equally adapted to radio frequencywelding or to any other type of means to secure said bent rung ends tosaid adjacent tape portions such as stapling, cementing, etc., althoughI obtain the best results faster employing radio frequency heat throughthe inturned ends and opposite tape portions and obtain a heater andbetter means of securement therefor.

In the embodiment shown in Figs. 23-25, I have supplementally welded thecontinuous longitudinal cords 42a and 421) between said inturned ends36a and 36b and opposite side portions 38a and 38b to provide specificmeans for limiting the stretch of the side tapes 34a and 34b in whichcase it is necessary to add suitable means for feeding said cords to myimproved machine.

A plastic ladder tape, however, may be provided which is stretchableonly up to 1% of the length thereof, preferably of a 12-24 gauge (.012to .024") thickness and which may comprise a vinyl resin having asuitable percentage of a stabilizer such as lead carbonate andplasticizer such as tricresyl phosphate incorporated therein sufficientto leave it flexible and still substantially nonstretchable, althoughany suitable heat sealable plastic or synthetic resin, preferably ofsuflicient thickness, may be employed. Suitable resin films for thispurpose are sold by the Bakelite Corporation under the trade name ofVinylite, the Peabody Plastic Products Company of Peabody,Massachusetts, under the trade name of Plasbro and by the RubberCorporation of America of Brooklyn, New York, under the trade name ofRucoam, etc.

In employing plastic tape for the side tapes 34a and 34b and the rungs32 of sufiicient thickness (12-24 gauge), welding marks on the walls ofthe tapes are substantially eliminated. When the cords 42a and 42b areemployed, these may comprise standard types of nylon stretch limitingcord.

In order to apply the radio frequency heat, I preferably employ movableconducting bars 44 and 44' to insert the plastic ladder rungs 32 and 32'between the spaced ladder tapes 34a and 34b with the ends 36a and 36bthereof adjacent said tapes in the same direction for a substantialdistance, and I apply the welding radio frequency heat from electrodesbrought opposite the outer portions of the side runs of the tapes inline with said upturned ends and the ends of the conducting bars, sothat the conducting bars may function in the welding process as well asmeans to bring the rungs into suitable alignment for welding.

In my preferred embodiment, for this purpose I provide a continuousmachine which feeds the jigs forward intermittently so that the rungends may be welded to the tapes during each stop between movements. Forthis purpose I employ a continuous conveyor 46 and rung holding meanssuch as said conducting bars 44 mounted on said conveyor spaced fromeach other the desired lengths between rungs.

I provide means 48 to load and hold a plastic rung 32 of greater lengththan said holding means 44 on the side of each rung holding means 44with its ends 36a and 36b projecting equal amounts from said rungholding means.

I provide means to bend said end portions 36a and 36b rearwardly andmeans to feed side tape strips 34a and 34b spaced from each other thedesired amount in the finished tape with said rearwardly turned rungends 36a and 36b abutting said spaced strips 34a and 34b.

I provide means to secure said bent rung ends to said spaced stripswhich, as stated, may comprise any suitable type of securing means andpreferably comprises the radio frequency welding means heretoforereferred to and I provide suitable means to operate said machine,including means to intermittently advance said conveyor equal amountscorresponding to a function of the distance between rungs with a stop between each movement thereof, the length of movement of such means beingdetermined by the number of rungs it is desired to weld at once and Iprovide means to actuate said rung loading and holding means during eachstop and means to actuate said securing means or welding means duringeach stop. I may, in addition, provide an overrun preventing stop lockfor said conveyor and means to move said lock into locking positionduring each stop and move it therefrom prior to the end of each stop. Imay also, if desired, provide means to strip completed tape from saidrung holding means and suitable means to actuate it.

While any suitable type of securing means may be employed, I preferablyemploy so-called radio frequency heating which develops heat in thedielectric plastic tape material, according to one theory by inductionor to another theory by molecular friction. Various types of radiofrequency generators may be employed. One is sold by the KabarManufacturing Corporation of New York. Another, entitled A Thermatron issold by the Radio Receptor Company, Inc., of New York, and the elementsof one in a sewing machine are described in Patent 2,432,412 issuedDecember 9, 1947, to the Singer Manufacturing Company, to function at afrequency between 27-200 megacycles. For this purpose, I provide a pairof high radio frequency electrodes 50a and 501) having universallymounted aligned welding button heads 52 mounted on said machine toreciprocate against and away from the sides of said tape strip portions38a and 38b opposite said rearwardly turned rung ends 36a and 36b, and Iprovide means to reciprocate said electrodes to abut the sides of saidtape strips opposite said 7" rung ends, and-ahigh-radio frequencygenera-.- tor 54 of the type hitherto described to: apply energy throughsaid electrodesiflaaand 50b, rearwardl y turned rung endslifigtvand36lrand. ad'- jacenttape portions38'a and 38b toquickl y weld the:bent: rung ends 36a and iifib to the opposite portionsaSBd and 38b of:said. tape 7 strips during each. stop. To actuate the electronicheatgenerator 54, I employ an electrical; circuit 5510011 .nected'thereto, a settable timer switch 58 connected to said circuit and; atimer switch.- start, ing switch 60' actuatedtby: the electrode applyingmeans-as the electrodes. 50a and th are moved inwardly to'weldingposition to startsaid timer switch to energize said electrodes duringeach stop;

addition, I; provide suitable-means operable on absence of a rung on anend of. a cross: bar" to stopithemachine which willbe described in: moredetail later, and means operable on? failure of saidstripping means-tostrip the completed tape from: said cross bars to stop the machine whichwill also be described in. more detail later;

It is. apparent, however, that" my improved method. may be accomplishedby any-type-of machine or even by hand, said method comprising the novelmethod of (I) i-nserting'a'plastic-ladder' rung between spaced. laddertapeswith the ends thereof bent adjacent said tapes for a substantialdistance, and" ('2 securing said bent ends directly: to said tape,preferably by applyingt: welding radio frequency heat through saidturn'e'd" endsiand opposite tape portions toweld said endsto said tape.

My preferred embodiment of machine, however; ispreferably constructed asfollows:

In the embodiment shown; said machine comprise an upright machineadaptedto' weld four rung ends at once, namely, the opposite rung-endsof apair-of staggered rungs during each stopof the: conveyor, althoughit is obvious that the operations may take place on a horizon-talrun ofthe conveyor instead" of on the two vertical-runs as show-nr In theembodiment shown, the frame III; comprises v askeletonupright oblongframe havingthevertical corner bars; 82 joined together respectively bythe cross top front and rear bars 65 and the top side-bars 66. Othercross bars may be provided, such as the=lowerfront cross bar Gil andsupplemental supporting sidebars a such as the top sprocket bearing;supporting side bars 12, the bottom sprocket bearing supporting sidebars it, the oscillating feed shaft bearing. supporting bars '55,. theoverrun preventing lock oscillating shait supporting bearing bars; 18'and the driveshaftsuppcrting bearing bars 80.

To mount the conveyor on the" frame; I provide the upper sprocket 8-2suitably'mounted on bearings 84* on said upper sprocket bearin'gisup-"porting. bars-1T2- and a lower sprocket 8G suitably mounted on bearings88mounted= on the" lower sprocket. bearing supportingbars- M; saidsprockets: 82- and" bit having. suitable teeth '89- adapted tosmeshwithsui tableholesthe chain con veyor; 55*. shown; The conveyor maybeset, ad iusted or' tightened. by raising or lowering its upper bearingBltby: means of theadjusting-bol'ts 83 and nuts 85;. V

The chain conveyor 46: iszthus continuous and: provides an endlessrunaround. said. sprockets providing: a straight upward rear: run 9danda straight. downward front run 9.3; Togsupportthe individual rungsformed and loaded thereon in a. manner tobe explained, I provide therung. holding jigs- 98 longitudinally spaced from each a other on theconveyor-41;, having thehatlbas plates I 0b mounted on saidchainconveyor IG to have the side edges I02 projectzlaterall y there from; Iprovide: insulating blocks I04 projecting upwardly onsai d-base platesof alengthisub stanti'ally the distance between the staggered? rungs andspaced apart ona straight run substantiallythe desireddistancebetweensaid rungs, having rung holding arms me and IDS-projecting forwardly from the front and rear edges thereof of spacedheightssubstantially" the:- desired horizontal spacingbetween rungs; I

In my preferred embodimental mount thezconducting cross bars or holdersi t; pref-er is: of rectangular shape -as-shown, on thetops ofi said'arms. I alsoprovide suitablemeans to-clamp each end of acutru-ngotgreatenlength-than said bars-tothe leading edgesof said" bars;so that the ends thereof-projectsubstantially equal amounts therefrom;comprising theivotany mountedfi-ngercl amps' I IO, having the p-ins 2projectinglaterally fromthe'-lower ends thereof; pivotally mountedcentrally on the side-Walls of said blocks IE4 as at I--Id-"-andhaving-the upper clamping ed'ges- IIG- adapted to abut theleading edgeof'each crossbar M-or- M" on" each sideof' sa-id-insulati-ngblocks to clamp each end' oteach rung tothe-leading edges of said bars,andI pro,- vide spring means I-I Scomprisingth'e 'coi'lspringsconnecting said clampsi oneach' arm together connected to the front endof the finger-clamp I Iil'opposite the leading cross bar and'the rearend of the finger clamp I'I'Il opposite the trailing;

cross bar 36".

To pivotall'y maintain. said. jigs. in. alignment; during the. straightupward and. downward. runs thereof, I provide the horizontallyspaced-verti cal sidebars I20. extending. along the upper, endsof, eachstraight run,, having cam plates I22 mounted, thereon to tilt. said jiclamps: III to. open positionand internal grooves I-24- receiving, theside edges. I 0-2 of said jig plates to ;retain-. said. jigs rigid andevenlyspacedontheir upward and downward runs. I provide, also,-,horizontallyspaced means for each set-.- of barsnamely, the leading setof bars 44 andthetrailingsetiofbars 44-, the ones for theleadingba-rs-I' l-being locate ed at a. horizontally spaced distance-abore the onefor the trailing bars, 44 staggered.

from each other: the: desired distance between;

rungs, tocut a plastic rung.- from a. continuous plastic strip; and:load and; hold it: on the: side of each bar withv its. ends. projectingsubstantially equal amounts from said bar on the upward rear run with.the: said clamping means f fltbeing releaeable during the insertion.operation by the. cams I22 whilecutti'n a plastic rung 32 01-12 froma-.continuous strip and loading iton'the side of each respective-bar.As-said-loadi-ng-meansare identical: for each. alternate staggered bar,I will describe one-in detail:

Said loading means comprises a. transverse base: plate I26 (126a orI266) mounted on said frame in. rear of said arms for this purpose, having the ends thereof mounted onthe rear corner bars I32. Each baseplatehas-a centralopen p01 tion' I28 of substantially thewidtlrof thejigcross bars- 44 and" has a knife slot I SII ati a closely spaceddistance on one end thereof, said end also having a rung tape spooli I32suitablymounted on a suitable: bracket I36mountedthere'om A2crossguid'eway l3ii'isprovided, having an open channel t38 neartheloweri end. thereof through whichthe tape end; Ito passes, providingthe free 9 tape end I adjacent said knife slot I30 urged upwardly by thespring I4I I also provide a flat guide spring I42 pressed downwardlyagainst the tape by the closed guideway. I also provide an elongatedopen guideway I44 on the opposite side of said base plate beyond saidopen portion I28, having an elongated reciprocal slide I46 mountedthereon, having a cam I48 having an upper surface I50 tapered downwardlyand outwardly and mounted substantially centrally of the upper surfaceof said slide I46. I also provide a clamp ing lever I52 centrallypivotally mounted as at I54 on brackets projecting upwardly from thecentral portion of said slide, having a straight rear end I56 and anormally upwardly tilted front end I58. A suitable hole I60 is providedin said slide I46 to receive the spring I62 to urge the rear end I56 ofsaid lever upwardly, tilting the front end I58 thereof downwardly toform a movable jaw to clamp the projecting end I40 of the ladder tapeI32 on the inner end of the stroke of said slide I46. I also provide anoverhead retaining bar I64 swivably mounted on said plate I26 to extendover the rear end I56 of said lever to press it downwardly to releasethe front movable jaw end I58 when the slide I46 is urged outwardly,swivelable by the rear end of said lever as it starts to move outwardly.The roller I65 mounted on said base plate abuts said rear end I58 nearits outermost position to release the tape after it is drawn the desireddistance outwardly when the bar I64 swings to its position near saidrear end.

It is thus obvious that with this construction when the slide I46 ispushed inwardly, so that its rear end no longer abuts the bar I64, thatthe spring I 62 will push the rear end I56 of the lever upwardly so thatits front movable jaw end I58 will clamp the free end of the tape I40 asshown in Fig. 10 and that as the slide I46 is drawn outwards, it willpull it across said opening I28 so that its end 36a will extend beyondsaid open portion I 28 substantially the amount that said knife slot I30is spaced from said open portion I28 and that the roller I65 will abutthe rear end I 56 to release the jaw end IE8 at that time. To clamp saidrung tape 32 to the base plate I26 during the cutting operation, Iprovide the spaced fingers I66 having their upper ends pivotally mountedon the pivot rod I68 mounted on said base plate to extend in rear ofsaid open portion I 28 with said spaced fingers I65 being mounted on theends of said pivot rod, and I provide the transverse bar I10 overlyingsaid fingers and a compression sprin I12 contacting the bar to presssaid fingers I 66 against said tape on opposite sides of said openportion. I also provide a knife blade I69 pivotally mounted on saidpivot rod I68, having a cutting edge movable downwardly into said knifeslot I30, and I provide a knife operating lever I14 pivotally mountedcentrally on brackets I16 projecting upwardly from said base plate,having an inner end I18 overlying said knife I69 and an outer end I80preferably having the roller I92 thereon exterior of said roller I 55,urged upwardly by said slide cam I48 on extreme inward movement of saidslide I46 to pivot the inner end I18 thereof to abut said knife I69 andurge it downward into said knife slot I30 to cut off the inner end ofsaid tape, and I provide spring means I84 to abut said blade I69 tonormally urge it to open posi tion.

It is thus obvious that on initial movement of the slide inward tooperating position that the jaw front end I58 of the lever I52 is heldupwardly by the bar I64 until it reaches its innermost position when therear end I56 leaves the bar I64 and is urged upwardly by the spring I62to the position shown in Figure 10, causing said front end I58 to nipthe free end I49 of the tape urged upwardly by the spring I4I. Then, asthe slide I46 is reciprocated to its outermost position, it will pullthe tape to the position shown in Figure 11, with equal length ends 36aand 362) on opposite sides of said open portion I28, when the rear endI56 of said lever I 52 will pass underneath the roller I 65 to againraise said front end I58 to release the tape. The fingers I 66 will thengrip the tape to retain it against the base plate I26 during the cuttingoperation and as the slide I46 approaches the outer end of its stroke,the roller I82 will ride up the cam I48 causing the knife I69 to enterthe slot I30 cutting off the end 361) of a rung 32, so that its lengthexterior of said open portion I28 will equal the length of the oppositeend 36a beyond said open portion and that as soon as the slide againstarts on its inward stroke, the knife lever I14 will ride free of thecam I48 and the spring I84 will urge the knife to its open position, andas soon as the conveyor and jigs start to move, the clamps III] willclamp the cut rungs 32 against the leading edges of the conducting crossbars 44.

I also provide means to feed the side strips 34a and 34b continuously tothe desired spaced distance from each other bending the ends 36a. and38b of the rungs 32 exterior of said bars rear- .vardly and for thispurpose, I provide the in wardly inclined guide bars I86a and I861)providing a chute extending downwardly from the upper end of the frameto each side of the straight downward run 96 of the jigs 99 terminatingsubstantially adjacent the sides of said jigs to bend the laterallyprojecting ends 36a and 38b of the rungs 32 and 32 upwardly orrearwardly between the side tapes 34a and 3412.

Each strip of tape 34a and 34b is mounted on a spool I88 mounted onbrackets I projecting upwardly on each side of the frame. The tapes 34aand 34b are then passed over the upper guide rolls interior of saidspools I88 and obliquely in line with the upper ends of said chute orguide bars or plates I86a and I86b.

To feed the tapes 34a and 84b evenly on each side of said jigs, Iprovide the takeup evener guide rolls I 94 pivotally mounted in anysuitable manner such as by the bails I96 on the pivot rods of the uppertape guide rolls I92 which abut the continuous runs of tapes 34a and 54bintermediate said upper guide rolls I92 and said spools I88 to flattenthe respective continuous runs 34a and 34b of the side tapes andmaintain them under even tension during the rung welding operation.

As stated hitherto, I may provide any suitable type of means such asstapling means, cementing means, lacquering means or electricalresistance heating means or otherwise to secure the ends 36a and 36b totheir adjacent tape portions 38a and 388 but I preferably for thispurpose employ radio frequency welding to heat the dielectric tapesufficiently to provide the positive strong Welds 49a and 46b and forthis purpose I mount a pair of similar high radio frequency electrodeson said frame to reciprocate towards and away from the sides of saidjigs immediately below the lower ends of said guide bars I86a and I86b.

In the embodiment shown, said electrodes 50a and 50b comprise themetallic cylindrical members 58a and 59b, having the threaded shanks.111 1'98 projecting outwardly therefrom. I mount the sleevles 2E9horizontally of the :adjacent portions 'of the front corner .bars 262and .I provide the cylindrical "rod portions .202 reciprocal in saidsleeves 208, to reciprocate said electrodes, said .rods also havingthreaded shanks 204 on the innerends thereof. I also provide blocks of:high frequency insulating material, in the embodiment shown comprisingthe frustro cones 206 having the threaded holes 269 centrally .of theouterends thereof and the threaded holes 2110 centrally of the innerends thereof. Whileany suitable type of high frequency insulatingmaterial may be employed, I preferably construct said blocks 206 out ofglass bonded mica. The respectiveshanks 198 of said electrodes '59:; and50b and 204 or" said rods 202 are threaded within said respective holes210 and 209.

As stated hitherto, the functioning surface 2| 1 of theelectrodes ispreferably universally mounted on the inner ends of the blocks 206, sothat each electrode will lie flat against its respective tape edgeduring the welding operation. In the preferred embodiment shown .Iprovide a structure which will weld the opposite two ends of a pair ofstaggered rungs 32 and 32 to therespective tapes 34a and 341) duringeach respective stop of the feeding mechanism. For this purpose, Iprovide the metal plates 212 of generally rectangular shape, having thecentral electrode receiving hole 2H3 of :slightly greater diameter thanthe electrodes 56a and 58b. I provide the transverse pivot pins 2|5extending through the inner-ends of the electrodes Mia-and 59b and-saidplates 21-2 exterior of said holes 2M topivotally mountsaid plates 2l2on said electrodes. Ialso provide each plate with the horizontal holes2H3 adjacent each end thereof, each having the countersunk inner ends220 and I provide the heat applying buttons 52 having the inner .heads222, having the preferably embossed inner surfaces 2 adapted to-contactsaid tapes 34a and 34bon the portions 38c and :38?) opposite theupwardly bent ends 36a and 36b of the short arm and long arm rungs 32and 32'. Said buttons 52 also have the Shanks 225 extendingthrough saidholes and semispherical portions 226 between said heads and shanks toabut the countersunk hole ends to universally mount each respectivebutton 52 on said electrodes 50a and 56b, and I provide suitable meansto secure the outer ends of said button shanks 22 5 "to said'plates 212,in my'preferred embodiment shown comprising the cotter pins 228 adaptedto extend through suitable holes 238 in the outer ends of said shanks.As shown, said electrodes 50a and 50b are so secured in the ends of saidblocks 205 that each plate 212 inclines outwardly from the jig shortarms to the jig long arms (Fig. 14).

It 'isapparent, however, that anyother suitable means may be employedfor universally mounting the heat applying surfaces 2 on the electrodes50a and 5% on their supporting blocks 205. In the embodiment shown, thewires 23i carrying the high radio frequency electricity are attached toeach respective electrode by a suitable connector 23'2, in theembodiment shown comprising a flat plate 234 having a hole 23% thereinsurrounding the shank I93 and abutting the inner cylindrical end of itsrespective electrodes 58a and =5flb adjacent the inner end or tip of theirustro conical insulating block 208, said plate 232 being-connected tothe wire 23l by any suitable type of :a connecting plug 231, such as thetype shown.

vAsstatedhitherto, to applythe high radiozfre- :q'uency heat throughsaid buttons 52 and "conducting bars "44 where employed, to quickly weldthe :upwardly ibent rung portions :36a'and 362) on a jig to the oppositeportions 38a and 38b oicsai'd tape, I provide the radio frequencygenerator 154 of the type hitherto described.

.As stated, .I provide suitable means to operate said machine, includingmeans .to intermittently advance'the conveyor equal amountscorresponding to the distance between ba-rsandrungs with asubmantialstop between each movement thereof. .I provide an over runpreventing stop lock for said conveyor and means to :move .saidfilockinto locking position during each movement :and remove it therefromprior to the .end :of each stop period. I provide means to actuatezsaidmeans '58 to cut, load and hold rungs on thesuccessive pairs ofconducting bars '44 and All :of said conveyor during each such stop. Ialso provide means to reciprocate said electrodes 59a and 50b to abutthe sides of said tape strips and rung ends interposed betweensaid tapestrips and ends-oi said conducting bars .during each stop. I providemeans to. strip .completedtape fromsaidbars. I provide mean-s to actuatesaid tape stripping means during each stop. To supply suitable heat, Iprovide an electric circuit 56 connected to the electronicheatgen'erator 54, a settable timer switch 58 connected in :said circuitand a timer switch .startingswitch fill actuated by the electrodeapplying means as it is moved "to weldin position to start said timerswitch to heat said electrodes during each stop.

in the building of the actual machine, certain portions of these .meansoverlap with each other and in :order to describe them I will describethe actualrstruotureiofthemachine.

In the machine, rt'hexmeans to strip completed tape from said jigscomprises a pivot shaft :238 mounted transversely of the front of theframe adjacent the end of the downward front run 55 of the conveyor,'an'inner bai1i240 having :its bail arms 242 pivo'tally mounted on saidpivot and a base 2% mounted on the lower ends ersaid arms 242, an outer'bail 2413 of slightly greater Width having its arms 2'48 also'pivotallymounted on saidisha'ft 238 and having a orresponding bail base .250comprising a rod mounted on the lower ends of said arms 248 coveredwith'rubber 252 or other :suitable material. Alink 2'54 joins one ofeach set of armst2 i2 and 248 together, having an encl'pivotallysecuredto the outer bail am 248 as at 258 and a lower end having alongitudinal slot 258 therein receiving the extended end of themner bailbase 244. An oscillatable shaft 26H is mounted centrally of saidfr'amahaving a crank arm 282 mounted thereon and aconnecting rod 264 ispivotally connected to the central portion of said link 254 and the saidcrank am 262, whereby on outward movement of said rod'2'5'4 said linkurges the inner bail base 244 against said outer bail base 250 to gripthe welded tape and pull it from said jigs, and on inner movement ofsaid connecting rod 264, said innerbail base 244 separates from saidouter bail base to "permit the stripped tape to drop between said bases'2 and 2 59.

While any suitable means to drive the machine may be employed, in theembodiment shown I preferably employ an electric .moto- 266 driven by"a'suitable'main circuit 26*8. I employ a main drive shaft 270 driven bysaid motor extending acrossthe front of the machine. In the embodimentshown, said drive shaft has a sprocket 2-7-2 13 mounted thereon and thecams 214 having inwardly facing cam surfaces 216 mounted on each endthereof exterior of said frame and a crank arm 280 mounted on the freeend thereof having a radial slot 282 therein. As the means tointermittently advance the conveyor, I provide the conveyor drive shaft284 oscillatably mounted transversely back centre in rear of saidelectrodes, having an elongated crank arm 286 projecting downwardly andforwardly therefrom, having a vertical hole 288 in the end thereof and acrank arm 290 projecting upwardly therefrom, a connecting rod 292 havinga lower end having a rod 236 projecting laterally therefrom adjustablymounted within the slot 282 on said main drive shatt crank arm 280 andextending through and a substantial distance upwardly beyond said hole286:n said conveyor crank arm 286, having stop means such as the locknuts 296 on the upper endthereof and a spring 298 interposed betweensaid lock nuts and conveyor crank shaft arm 286.

I provide the oscillatable arms 300 spaced from each other substantiallythe width of the jig plates I 00 rigidly mounted on said conveyor driveshaft 284 extending forwardly to adjacent said jig. plate ends I02,having pivot pins 302 projeoting laterally from the upper portions ofthe front ends thereof and having means such as thejstop pins 304 on thelower portions thereof projecting laterally inwardly of said pivot pins302. Each arm 300 has a finger lever 306 having a central longitudinalslot 308 receiving said arm pivot pin 302, and a downwardly taperedupper surface 3I0 adjacent the inner end thereof and a pin 3I2projecting laterally from the outer end thereof and a spring 3I4 joiningsaid pivot pin 302 to said outer pin 3I-2, whereby said fingers 306 mayabut a jig plate end I02 to move the con veyor forward the length ofsaid jigs on each downward movement of the crank am 360 and said fingers306 may pivot and slide inward-1y as shown in Fig. 16, so that theirinner ends 3 I 0 may pass the said jig plate ends and conveyor on eachupward movement of the crank arm 300. It is thus obvious that with thisconstruction the motor drives the main drive shaft 210 which, throughthe medium of the crank arm 260 and connecting rod 296, oscillates theconveyo drive shaft 284 so that the pivot fingers 306 may move it-forward the distance between rungs or jigs on each oscillation thereofon each rotation of said drive shaft. I also provide an over runpreventin stop lock fo said conveyor comprising an oscillatable rod 3I6transversely pivotally mounted on the front upper portion of the frameimmediately in rear of said conveyor, a downwardly curved cam arm 3 I '8mounted thereon extending rearwardly therefrom urged upwardly by saidconveyor drive shaft crank arm 230, spring means 320 connected to saidarm 3| 8 and to said frame to normally urge said arm 3 I 8 downwardlyagainst said upwardly projecting conveyor drive shaft crank arm 290 anda stop looking plate 322 adjustably secu-rable to said oscillatable rod3I6 by means of the set screw 324 to pivotally mount it on saidoscillatable rod having aligned pairs of teeth 326 projecting inwardlytherefrom thefdis'tanoe between the leading edges of said jig plates,whereby when said drive arm 284 is oscillated by said main drive shaft,said arm 3I 6 mounting said over run preventing stop plate 322 may besimilarly oscillated by the spring 320, so that said teeth 326 will beoscillated into position abutting the leading edges of said jigs at theend of the period that the arms 300 serve to urge the conveyor forward,and will be withdrawn therefrom by the arm 296 contacting the cam arm3I8 connected to said stop drive shaft 3I6 as soon as said stop periodis over.

In the embodiment show-n, the means to oscillate said electrode rods 202comprise the levers 328 pivotally mounted centrally thereof on thebrackets 330 projecting laterally from the frame, having the upper ends332 pivotally secured to the outer ends of said electrode rods in anysuitable manner such as by the bolts and cotter pins shown at 334 andthe lower ends in the embodiment shown having the cylindrical extensions336 adapted to abut the face cams 216 on the inner ends of the cams 274on the ends of the main drive shaft 210 to urge said electrode rods 202outwardly after the welding operation as the extensions 336 abut thehigh portions 338 of said cams during the conveyor feeding period.Spring means 340 are provided to urge the electrode rods 202 inwardlywhen said extensions 336 abut the low portions 342 of the cams duringthe stop welding period. For this purpose, the right angle cranks 344have their bases 346 pivotally mounted on pivot pins 348 on extensions350 projecting laterally from the side walls of the frame. Said cranks344 have downwardly projecting arms 352 abutting the ends 354 of theelectrode rods 232 and outwardly projecting arms 356. The springs 340have their upper ends attached to the outer ends 358 of said outwardlyprojecting arms and their lower ends attached to extensions 360projecting outwardly from the frame below them. It is thus obvious thatwith this construction that as the cylindrical portions 336 of the lowerends of the levers 328 abut the low portions 342 of the cams 216, thatthe springs 346 will urge the crank arms 356 downwardly so that theirdownwardly projecting crank arms 354 will abut the outer ends of theelectrode rods 202 to urge the electrodes 50a and 50b and their heatapplying surfaces 2| I against the portions 38a and 38b of the sidetapes 34a and 34b opposite the rearwardly turned ends 36a and 36binterposed between the ends of the conducting bars 44 and said sidetapes 34a and 34b to apply a welding heat through the dielectric plasticside tapes and i-nturned ends to provide the welds 46a and 40b joiningsaid inturned ends 33a and 36b to said side tapes 34a and 341) duringthe stop Welding period after the welding heat is generated in themanner to be explained. It is obvious any suitable means, pneumatic,hydraulic or otherwise may be employed to oscillate said electrodes.

To provide means to actuate the loading mechanisms 48, I provide therear drive shaft 362 having the drive sprocket 364 thereon and the chain366 connecting the sprocket 212 on the front main drive shaft 216 withthe sprocket 364 on said rear drive shaft 362, said rear drive shafthaving an arm 360 to oscillate said spaced slides HM and I461) for therespective upper long run arms 44 and said lower short run arms 44',with said arm 368 projecting from the free end of the rear drive shaftopposite the motor 266. I provide the pivotally mounted cranks 376a and31% for each slide I 46a and I461), having the respective upwardlyprojecting arms 312a and 312i) shown, pivotally connected to theirrespective slides I46a and M6?) by the pintles 314a and 3141) and theinwardly projecting arms 316a and 31Gb. I provide a verticallyreciprocal rod 318 connected to said inwardly projecting ar-ms 316a and3'I6b by the bolts 380a and 3802). I also provide a supplemental arm 382having an upwardly bent inner end .38 4 connected centrally. to theupwardly projecting arm. 3127) .on: the. lower short arm crank am .3101):by' the bolt 386, said arm having a stop 388 thereon normally abuttingthe outer edge of the upwardly projecting-arm 31212 of said crank 319i)and Irprovide safety spring means 389 connectingzsaidupwardly bent arm'end 384 and said upwardly projecting crank arm 3i 2b and I provide.ailink .390 which may he adjustable in any 'suitable-manner'such asshown at 392, having an upper end connected to'the outer end 394xii-said suplement-al arm 382 anda lower end connected to the arm36 8:on saidrea drive shaft :362. II also provide the adjustingcounterbalancing :weights -396onthe lower end of said :veijtical rod318. It is obvious that the spring ;3'89-.;and=the'weights 396 providean easy, even movement for the slides 46a and 'l'4 5bnat all times.

To actuate the stripper mechanism ,1 provide an additional arm 398;mounted onsaid rear drive shaftanda drive arm'40il mounted on saidstripper-pivot shaft 265 and a link 402 joining said arms 3 98 and 40,0together to oscillate said stripper shaitifiU-to actuate the strippermechanism I ingthe mannerlhitherto explained.

:As -state.d,,I also provide stop motion mechanisms forstopping themachine inthe event that airung end does-notcover each end of aconductingrod :44 and in' the event that the finished tape isnotstripped cleanlyifrom the jigs. As these stop .motion mechanisms,however, are right onithegmachine, it is essential that theyiunctionpnalow voltage such at 12 volts, compared to the voltagerequired to heat the electrodes 550a, andi50b and actuate the motor 268..The :circniti-from the main line 268 is connected by thedine 401.170the electronic heater 54 which inturn is connectedto the electrodes 50aand 50b by ith:e.line 4ll6"or .56 through the respective conducting,bars44rand 44'. Current from the main iineisalsoconducted through the line:408 to the motor zpush button'main switch 4) through the "sw'itch 4i2ofthe magnetic relay switch inv said .maincircuit by theline 4h; or 253 tothe motor .Abranchilillfi of the. line 408 leads to the transformer-M8in saidmain circuit to transform the wnltagexfrom the high voltage coil420 thereof to the lowvoltage coil 422 thereof, and I provide-asecondaryucircuit 424 of much lower voltage connected to'said secondarycoil 422 connected by the branch 426 to .the coil 428 of the relay 430to actuate the switch 432 thereof.

.Therelay switch 432 is connected .by the primaryline'434 to thesolenoid436 of a magnetic make and break switch which is also connectedby the branch line 431 to the primary line 408, the :switch 412 of whichis connected to the .branch4l4 ofthe main primary circuit, as explalned.

.Asthe stop motion to stop themachine in the event arung end is notloaded on each end of a conducting bar 44 or 44, I provide the metalstrips438'a and 438i) adapted to abut the respective ends of the bars 44and 44 as they pass by on the conveyor, projecting inwardly in the pathsof the ends of the connecting cross bars of the arms-of the jigs. If thecross bars are properly loaded with plastic rungs 32 on the leadingedges thereof, theprojecting ends 36c and 35b thereof will be interposedbetween the metal strips 438a and the conducting ends of the bars 44.Should, however, no rung be mount-ed on there at all, or ancend 3611 or36b should not be-suitablygripped thereon,.the secondary current.willpass through the two adjacent respective metal strips 438a and438i) temporarily :connected through -a bar '44 or 44. Should thiscontingency oocur,.current will pass through the lines *424 and'426 to.actuate the =solenoid-428 of the relay switch-43cm break the primarycurrent in the line 434 to-actuate the solenoid 436 to break themagnetic switch 4l2 to shut ofi" the motor 266.

In orderzto stop themachine, in the eventthat the tape is not :beingsuitably stripped therefrom, I provide theswitch 440 connected to abranch 442 of .said secondary circuit having a pivotal switch arm 444.pivotally connected to :one line pivotal to abut acoritact 446 in theotherline thereof, and I provide theielongated switchlever 448pivotally'mountcd on the frame as :att450 having :axshort armi4t52 toabut'said switch arm 444 to close theswitch i440 and a long am extendingunderneath the stripped completed tape :and the jigs 98. When-thestripping mechanism functions. to strip. the tapefromthe j-igs98, thearm i454always remains free of. the tape, .but should it fail to stripthe tape from the jigs 98., the unstripped tape function .tomove the arm454 downwardly and inwardlyto close theswitch 440 to actuateitherelay.430 to actuate :the'magnetic switch'solenoi'd 436 to function tostopzthe motor .265 in: the T manner. hitherto explained.

As stated, to regulate the'timeof feeding, if desired I may provide .aisettable Itimer switch .456 or 58 having a suitable dial'458 and asettable pointer 468 so that the .pointer':may betset to regulate thetime of heating. Thetimer switch 456 is connected to theelectronichea'terby the line 462 and-to the mainline bythe line 454. Tostart the timer switch I provide the line 456 extending to a timerswitchistarting switch468'or 60 having the movable switch blade 410normally urged :to open position by the spring 412,:but movable toaclose'd position abutting the contact 414 'on the opposite line ofsaidbranc'h line 466. Said'timer switch starting switch 458 is actuatedby the electrode rod applying means as an electrode rod 202 is pushedinwardly to start the functioning of the timer switch 456 and for thispurpose, asshown, is mounted on thelower endof theleverarm1328to beclosed by the "lower portion of said "arm as it moves outwardly'as thespring 340 urges said electrode rod 292 inwardly. It is obvious,however, that :any projection mounted on any suitable portion of themachine, suchas on the exterior surface of the cam 214, may be employedto actuate said switch 458 "in the desired portion of the cycle atthe-startingof the stop period audit is obvious that the timer switch456 is set to apply heatthrough the electrodes through the desiredportion of the stop period of said cycle. If desired, however, the timer456 may .be dispensed with and the time of heating controlled bythelength of a cam;

In general, the various :parts 'of the machine are so operated that thefeeding means only functions to feedthe conveyor during aportion of thecycle and that all the other operations hitherto described are set tofunction during the stop portion of the cycle. -The operation .of themachine has already been described in the operation of each individualpart thereof, and it is obvious that all the operative has to do is toload the spools I88 with the continuous strips for the side tapes 34a,and 34b and the spool for the continuous strip I32 for the rung tapesrespectively, press the push button 4H] and the machine will operate .tosuccessively produce plenished. 'The welds 46a and liib cause laddertape, feeding intermittently and welding intermittently during eachrotation of the main drive shaft 2'10 until the spools are exhaustedwhen the machine may be stopped and rehe continuous side strips 350: and3 th to be fed by the cross bars of the conveyor. It is also obviousthat the device is substantially fool-proof as the two stop motionsdescribed function to stop-the machine on failure of loading a rungproperly or on failure of proper stripping.

It is thus apparent that I have provided a machine which may be runcontinuously invoiving a new mode of operation, a novel method of makingladder tape and a novel ladder tape, all with the advantages describedabove.

It is understood that my invention is not limited to the specificembodiments shown or methods described, and that various deviations maybe made therefrom without departing from the spirit and scope of theappended clams.

What I claim is:

1. A machine for intermittently securing plastic ladder rungs tocontinuous runs of spaced ladder tape strips comprising a continuousconveyor, rung holding means mounted on said cc-nveyor spaced from eachother the desired lengths between rungs, means to load and hold aplastic rung of greater length than said holding means on a side of eachrung holding means with its ends projecting equal amounts from said rungholding means, means to bend the end portions of said rungs rearwardly,means to feed tape strips spaced from each other the desired amount inthe finished tape with said rearwardly turned rung ends abuting saidspaced strips, means to secure said bent rung ends to said spacedstrips, and means to operate said machine including means tointermittently advance said conveyor equal amounts corresponding to afunction of the distance between rungs with a stop between each movementthereof, means to actuate said rung loading and holding means duringeach stop, and means to actuate said securing means u i each stop.

2. Apparatus according to claim 1 having an overrun preventing stop lockfor said conveyor and means to move said look into locking positionduring each stop and remove it therefrom prior to the end of each stop.

3. A machine according to claim 1 having means to strip completed tapefrom said rung holding means and means to actuate said means to striptape from said rung holding means.

4. A machine for intermittently welding plastic ladder rungs tocontinuous runs of spaced ladder tape strips, comprising a continuousconveyor, conducting cross bars insulatedly mount ed on said conveyorspaced from each other the desired length between rungs, means to loadand hold a plastic rung on the side of each bar with its ends projectingsubstantially equal amounts from said bar, tape strip holding meansmounted on each side of the conveyor in front of said means, inwardlyinclined tape strip guide bars extending inwardly from the outer edgesof the frame to each side of a straight run of the bars terminatingsubstantially adjacent the ends of said bars to bend the laterallyprojecting end portions of the rungs rearwardly against the tape strips,a pair of high radio frequency electrodes having universally mountedaligned welding button heads mounted on said frame to reciprocateagainst and away from the sides of said tape strips opposite said rungrearwardly turned ends opposite the ends of saidconducting cross barsimmediately after said guide bars and means to operate said machine,including means to intermittently advance said conveyor equal amountscorresponding to the distance between bars and rungs with astop betweeneach movement thereof, means to actuate said means to load and holdrungs on the successive conducting bars of said conveyor during eachstop, and a high radio frequency generator to apply induction heatthrough said electrode buttons and conducting bars to quickly weld thebent rung ends on the conducting cross bars to the opposite portions ofsaid tape strips during each stop.

5. A machine for welding plastic ladder rungs to continuous runs ofspaced ladder tape, comprising movable conducting bars to insert plasticladder rungs between spaced ladder tapes with the ends thereof bentadjacent said tapes in the same direction for a substantial distance,with alternate rungs laterally staggered from each other to providealigned rows of rungs on each side of said tape and means to apply aWelding radio frequency heat through said upturned ends of a pair ofstaggered rungs opposite tape portions and conducting bars to weld saidends to said tapes.

6. A machine for welding plastic ladder rungs to continuous runs ofspaced ladder tape, comprising movable conducting bars to insert plasticladder rungs between spaced ladder tapes with the ends thereof bentadjacent said tapes in the same direction for a substantial distance andmeans to apply a welding radio frequency heat through said upturned endsopposite tape portions and conducting bars to weld said ends to saidtapes.

7. A machine for positioning plastic ladder rungs between and securingthem to continuous runs of spaced ladder tape comprising feeding meansfor advancing two strips of ladder tape in spaced parallel relation apredetermined distance apart, a. plurality of movable rung-holding jigseach including a spacing bar said jigs being movable from outside ofsaid ladder tapes to a predetermined position therebetween to therebyinsert and locate plastic ladder rungs between said strips of laddertape with the ends thereof bent adjacent said tapes in the samedirection, and securing means to cooperate with said bars to attach thebent ends of said rungs to said tapes.

8. A machine for positioning plastic ladder rungs between and securinthem to continuous runs of spaced ladder tape comprising feeding meansfor advancing two strips of ladder tape in spaced parallel relation apredetermined distance apart, a plurality of movable rung-holding jigseach including a spacing bar said jigs being movable from outside ofsaid ladder tapes to a predetermined position therebetween to insert andlocate plastic ladder rungs between said strips of ladder tape with theends thereof bent adjacent said tapes in the same direction, securingmeans adapted to cooperate with said bars to attach the bent ends ofsaid rungs to said tapes, and stripping means for removing said rungsfrom said jigs after said rung ends have been secured to said tapes.

EDWARD JANOVI SKI.

(References on following page) REFERENCES CITED The following referencesare of record in the file of this patent:

UNITED STATES PATENTS Number Name Date Straus Oct. 20, 1931 Newton Oct.17, 1933 Roscoe Aug. 6, 1940 Dillman May 26, 1942 Clark July 21, 1942Strickland Aug. 1, 1944 Preston June 12, 1945 Number Number Name DateHunter Aug. 13, 1946 Sherman Dec. 24, 1946 Brown June 17, 1947 AuxierApr. 20, 1948 FOREIGN PATENTS Country Date Great Britain Nov. 23, 1945OTHER REFERENCES Hoyler, An Electronic Sewing Machine, 1943 issue ofElectronics (7 pages).

